Researchers at Ludwig-Maximilians-Universität (LMU) have investigated a blood-based host response test for its suitability for the early detection and prediction of tuberculosis (TB) in household contacts in Africa. The test showed good accuracy in detecting active disease, but proved to be only moderately accurate in predicting future cases.

As the LMU researchers led by Professor Katharina Kranzer and Dr. Norbert Heinrich report in the journal “The Lancet Infectious Diseases”, household contacts of TB patients have an increased risk of developing the disease by about two percent. So far, it has been difficult to detect tuberculosis in its early stages or to predict who will actually fall ill. Therefore, preventive treatment is only used to a limited extent. Most contacts are asymptomatic, and current symptom- and sputum-based procedures often overlook early or latent infections.

In a large prospective study within the ERASE-TB consortium, the team tested the Cepheid Xpert MTB Host Response (MTB-HR) test on more than 2000 household contacts aged ten years and older in Tanzania, Zimbabwe and Mozambique. The participants were regularly examined clinically, imaging and laboratory for up to two years. At each visit, a fingerprick blood sample was analyzed with the GeneXpert system. The study was funded by the European and Developing Countries Clinical Trials Partnership (EDCTP2).

The MTB-HR assay had shown a good ability to distinguish between people with and without active tuberculosis. His predictive power for future illnesses was moderate and worked best shortly before the onset of the disease. Although the positive predictive value is higher than that of conventional immunological tests, it does not meet the WHO criteria for a sole screening or prediction instrument.

The results suggested that immune-based tests could improve both the detection of active tuberculosis and the identification of at-risk individuals. This would enable more targeted screening and prevention strategies to be implemented, unnecessary preventive treatments to be reduced and TB control programmes to be made more efficient. The researchers emphasized that such tests must be tested in real environments.

Original paper:

Larsson L, Olaru I, Behnke A et al.: Diagnostic and prognostic accuracy of the Mycobacterium tuberculosis host response 3-gene cartridge among tuberculosis household contacts in Mozambique, Tanzania, and Zimbabwe: a prospective, longitudinal, diagnostic and prognostic accuracy cohort study. The Lancet Infectious Diseases, 2026
https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(26)00114-3/fulltext
DOI: https://doi.org/10.1016/S1473-3099(26)00114-3

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